Start off by making a slip knot as if you are starting a chain. Insert the hook where you want to start the surface slip stitching, grab the loop you just made and pull it through.
Once you have the loop pulled through, it will look like this. The entire piece can easily slide through the hole, so hold on to the tail to prevent any slippage.
Insert hook into next stitch, pull up a loop and complete the slip stitch.
Continute until you have the desired design. This is what it will look like if you are doing the booties.